[@astrojs/lit] Fix slotted content (#5776)

* Fix add the missing slot attribute to child nodes * Add lit slot tests * Add changeset
withastro · Jan 6, 2023 · 6a31433 · 6a31433
1 parent 2b750a2
commit 6a31433
Show file tree

Hide file tree

Showing 8 changed files with 87 additions and 23 deletions.
diff --git a/.changeset/kind-beers-give.md b/.changeset/kind-beers-give.md
@@ -0,0 +1,6 @@
+---
+'astro': patch
+'@astrojs/lit': patch
+---
+
+Fix Lit slotted content
diff --git a/packages/astro/test/fixtures/lit-element/src/pages/slots.astro b/packages/astro/test/fixtures/lit-element/src/pages/slots.astro
@@ -7,9 +7,33 @@ import {MyElement} from '../components/my-element.js';
   <title>LitElement | Slot</title>
 </head>
 <body>
-  <MyElement>
-		<div>default</div>
-		<div slot="named">named</div>
+  <MyElement id="root">
+		<div class="default">my-element default 1</div>
+		<div class="default">my-element default 2</div>
+
+		<h1 slot="named">my-element named 1</h1>
+		<h2 slot="named">my-element named 2</h2>
+
+		<ul slot="named" id="list">
+			<li>Custom elements</li>
+			<li>Shadow DOM</li>
+			<li>HTML templates</li>
+		</ul>
+
+		<my-element id="slotted" slot="named">
+			<h3 class="default">slotted my-element default</h3>
+
+			<div slot="named">slotted my-element named 1</div>
+			<div slot="named">slotted my-element named 2</div>
+
+			<MyElement id="slotted-slotted" slot="named">
+				<h4 class="default">slotted slotted my-element default 1</h4>
+				<h5 class="default">slotted slotted my-element default 2</h5>
+
+				<div slot="named">slotted slotted my-element named 1</div>
+				<div slot="named">slotted slotted my-element named 2</div>
+			</MyElement>
+		</my-element>
 	</MyElement>
 </body>
 </html>
diff --git a/packages/astro/test/fixtures/lit-element/tsconfig.json b/packages/astro/test/fixtures/lit-element/tsconfig.json
@@ -1,3 +1,5 @@
 {
-  "experimentalDecorators": true
+  "compilerOptions": {
+    "experimentalDecorators": true
+  }
 }
diff --git a/packages/astro/test/lit-element.test.js b/packages/astro/test/lit-element.test.js
@@ -70,15 +70,35 @@ describe('LitElement test', function () {
 		const html = await fixture.readFile('/slots/index.html');
 		const $ = cheerio.load(html);
 
-		expect($('my-element').length).to.equal(1);
+		const $rootMyElement = $('#root');
+		const $slottedMyElement = $('#slotted');
+		const $slottedSlottedMyElement = $('#slotted-slotted');
 
-		const [defaultSlot, namedSlot] = $('template').siblings().toArray();
+		expect($('my-element').length).to.equal(3);
 
-		// has default slot content in lightdom
-		expect($(defaultSlot).text()).to.equal('default');
+		// Root my-element
+		expect($rootMyElement.children('.default').length).to.equal(2);
+		expect($rootMyElement.children('.default').eq(1).text()).to.equal('my-element default 2');
 
-		// has named slot content in lightdom
-		expect($(namedSlot).text()).to.equal('named');
+		expect($rootMyElement.children('[slot="named"]').length).to.equal(4);
+		expect($rootMyElement.children('[slot="named"]').eq(1).text()).to.equal('my-element named 2');
+		expect($rootMyElement.children('[slot="named"]').eq(2).attr('id')).to.equal('list');
+		expect($rootMyElement.children('[slot="named"]').eq(3).attr('id')).to.equal('slotted');
+
+		// Slotted my-element first level
+		expect($slottedMyElement.children('.default').length).to.equal(1);
+		expect($slottedMyElement.children('.default').eq(0).text()).to.equal('slotted my-element default');
+
+		expect($slottedMyElement.children('[slot="named"]').length).to.equal(3);
+		expect($slottedMyElement.children('[slot="named"]').eq(1).text()).to.equal('slotted my-element named 2');
+		expect($slottedMyElement.children('[slot="named"]').eq(2).attr('id')).to.equal('slotted-slotted');
+
+		// Slotted my-element second level
+		expect($slottedSlottedMyElement.children('.default').length).to.equal(2);
+		expect($slottedSlottedMyElement.children('.default').eq(1).text()).to.equal('slotted slotted my-element default 2');
+
+		expect($slottedSlottedMyElement.children('[slot="named"]').length).to.equal(2);
+		expect($slottedSlottedMyElement.children('[slot="named"]').eq(1).text()).to.equal('slotted slotted my-element named 2');
 	});
 
 	it('Is able to build when behind getStaticPaths', async () => {

diff --git a/packages/astro/test/ssr-lit.test.js b/packages/astro/test/ssr-lit.test.js
@@ -25,7 +25,7 @@ describe('Lit integration in SSR', () => {
 	}
 
 	it('Is able to load', async () => {
-		delete globalThis.window;
+		delete globalThis.window; // On Windows this results in `ReferenceError: window is not defined`
 		const html = await fetchHTML('/');
 		const $ = cheerioLoad(html);
 		expect($('#win').text()).to.equal('function');

diff --git a/packages/integrations/lit/package.json b/packages/integrations/lit/package.json
@@ -33,7 +33,8 @@
     "test": "mocha"
   },
   "dependencies": {
-    "@lit-labs/ssr": "^2.2.0"
+    "@lit-labs/ssr": "^2.2.0",
+    "parse5": "^7.1.2"
   },
   "devDependencies": {
     "astro": "workspace:*",

diff --git a/packages/integrations/lit/server.js b/packages/integrations/lit/server.js
@@ -1,6 +1,7 @@
 import './server-shim.js';
 import '@lit-labs/ssr/lib/render-lit-html.js';
 import { LitElementRenderer } from '@lit-labs/ssr/lib/lit-element-renderer.js';
+import * as parse5 from 'parse5';
 
 function isCustomElementTag(name) {
 	return typeof name === 'string' && /-/.test(name);
@@ -58,12 +59,22 @@ function* render(Component, attrs, slots) {
 		yield '</template>';
 	}
 	if (slots) {
-		for (const [slot, value] of Object.entries(slots)) {
-			if (slot === 'default') {
-				yield `<astro-slot>${value || ''}</astro-slot>`;
-			} else {
-				yield `<astro-slot slot="${slot}">${value || ''}</astro-slot>`;
+		for (let [slot, value = ''] of Object.entries(slots)) {
+			if (slot !== 'default' && value) {
+				// Parse the value as a concatenated string
+				const fragment = parse5.parseFragment(`${value}`);
+
+				// Add the missing slot attribute to child Element nodes
+				for (const node of fragment.childNodes) {
+					if (node.tagName && !node.attrs.some(({ name }) => name === 'slot')) {
+						node.attrs.push({ name: 'slot', value: slot});
+					}
+				}
+
+				value = parse5.serialize(fragment);
 			}
+
+			yield value;
 		}
 	}
 	yield `</${tagName}>`;

diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml